1. Field of the Invention
The present invention relates to catheter assemblies, loading trays, and methods of loading a catheter assembly. More specifically, the present invention relates to loading trays that improve the process of loading a medical device on a catheter assembly.
2. Background
Recently, minimally invasive approaches have been developed to facilitate catheter-based implantation of valve prostheses on the beating heart. These approaches eliminate the use of classical sternotomy and cardiopulmonary bypass. For example, French Patent Application No. 99 14462 illustrates a technique and a device for the ablation of a deficient heart valve by percutaneous route, with a peripheral valvular approach. Published International Application (PCT) Nos. WO 93/01768 and WO 97/28807, as well as U.S. Pat. No. 5,814,097 to Sterman et al., U.S. Pat. No. 5,370,685 to Stevens, and U.S. Pat. No. 5,545,214 to Stevens illustrate techniques that are minimally invasive as well as instruments for carrying out these techniques.
A valve prosthesis formed by attaching a valve to a frame made of a wire or a network of wires has been proposed. Such a valve prosthesis can be contracted radially to introduce the valve prosthesis into the body of the patient percutaneously through a catheter. The valve prosthesis can be deployed by radially expanding it once positioned at the desired target site. U.S. Pat. No. 3,657,744 to Ersek discloses a cylindrical, frame-supported, tri-leaflet tissue heart valve that can be delivered through a catheter assembly. The valve prosthesis is mounted onto a distal tip of the catheter assembly prior to delivery to the target location where the valve prosthesis is expanded into place.
Current techniques for delivering prosthetic heart valves through a catheter assembly include a transapical approach for aortic valve replacement. A crimped, valve prosthesis reversibly coupled to a distal tip of a delivery catheter assembly is transcatheterally advanced toward the native valve, where it is either forcefully deployed using a balloon catheter, or, alternatively, passively deployed using a self-expandable system. Accurate positioning of the replacement valve in the native annulus is critical to the success of the implantation.
To prepare such a valve prosthesis for implantation, the valve prosthesis can be initially provided in an expanded or uncrimped condition, then crimped or compressed around the distal tip of the catheter assembly until the valve prosthesis is as close to the diameter of the distal tip as possible. Various methods and devices are available for crimping the valve prosthesis onto the catheter's distal tip, which may include hand-held devices or tabletop devices, for example. These crimping devices can initially provide an opening that is large enough to accommodate a valve prosthesis in its expanded condition and be positioned over a desired section of a distal tip of the catheter assembly. This valve prosthesis can then be compressed by reconfiguring the opening of the crimping device to uniformly decrease the size of the opening until the valve is compressed to the desired size.
Loading a valve prosthesis on the catheter assembly, however, can be difficult as the valve prosthesis and crimping device must be carefully inserted over the distal tip of the catheter assembly without damaging the valve. Damage to the valve should be avoided. Accordingly, there is a need for a loading apparatus that securely holds the catheter assembly without use of a user's hands. Such restraint would allow a user to carefully align the valve prosthesis with the distal tip of the catheter assembly with two hands.
Further, the entire process of crimping and loading a valve prosthesis onto a catheter assembly, including crimping the valve prosthesis with the crimping device, positioning the prosthesis valve and the crimping accessory on the catheter assembly, and removing the crimping accessories from the catheter assembly should be performed in a saline bath that submerges the valve prosthesis. Submerging the valve prosthesis in the saline bath reduces risk that the valve prosthesis will be contaminated before being introduced into the body. According, there is a need for a loading tray that ensures that any user of a catheter assembly loads the valve prosthesis under the optimal conditions.